Date: Mon, 12 Mar 2001 12:59:05 -0800 From: Alfred Perlstein <bright@wintelcom.net> To: Soren Schmidt <sos@freebsd.dk> Cc: Kevin Oberman <oberman@es.net>, mobile@FreeBSD.ORG, stable@FreeBSD.ORG Subject: Re: Disk I/O problem in 4.3-BETA Message-ID: <20010312125905.X18351@fw.wintelcom.net> In-Reply-To: <200103122036.VAA99695@freebsd.dk>; from sos@freebsd.dk on Mon, Mar 12, 2001 at 09:36:27PM %2B0100 References: <200103122031.f2CKVRs19327@ptavv.es.net> <200103122036.VAA99695@freebsd.dk>
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* Soren Schmidt <sos@freebsd.dk> [010312 12:37] wrote: > It seems Kevin Oberman wrote: > > I'm not too sure if this belongs in mobile or stable. I reported the > > problem last week, but have seen no comments. Either it's something > > unique to my system (or my hardware) or people have not been doing > > large disk copy operations. > > > > My disk I/O performance has tanked after a cvsup on March 1. > > Subsequent updates have not made a difference. > > Some of this might be due to write caching being turned off as > default now, this was done due to "popular demand" because > write caching can hose your filesystem on a power outage. > > > Specifics: System ran normally until the March 1 cvsup. The prior > > cvsup was February 24. > > > > Prior to March 1 I could dd a 4 GB slice in 580 seconds (or a bit > > under 10 minutes). After March 1 the same exact command took just > > under 40 minutes to complete. The same was seen copying a 2 GB > > slice. It increased from 5 minutes to 20 minutes. No kernel > > configuration changes were made. > > This is worse than expected, try to use option ATA_ENABLE_WC > and see what gives, if its not back to normal we have to look elsewhere. Mr ATA, is there no ATA command to "syncronize cache" like in SCSI? -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] Daemon News Magazine in your snail-mail! http://magazine.daemonnews.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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